“In the past, we made money first and could only talk about the environment later. But it’s clear the government has changed its mind,” he said. “We can see everything is starting to move in the right direction.”

During the creation of the nightmarish airpocalypses portrayed in Wu’s artwork, pollution levels might have been 20 or even 30 times higher. “Beijing was like a giant airport smoking room that day. It was an epic haze,” he recalled, pointing to an image staged in January 2013 in which a girl appears to inhale oxygen through a tube connected to two heart-shaped balloons.

Wu says he became an artist after he saw foreign athletes wearing facemasks at the 2008 Beijing Olympics. Photograph: Tom Phillips/The Guardian

Traditionally, winter is Beijing’s smoggiest season, as coal burning ramps up to keep millions of residents warm. But the skies over China’s capital have been almost inconceivably clear of late, thanks partly to a government crackdown on the use of the fossil fuel.

Beijing enjoyed a record 226 days of “good” air quality last year and endured 23 heavily polluted days, compared with 58 in 2013, state media announced last month. The South China Morning Post, a Hong Kong newspaper, greeted the recovery with the incredulous headline: “How did Beijing become one of China’s top cities for air quality?”

Hu Xijin, the editor of the party-controlled Global Times, tweeted alongside a photograph of Beijing’s azure-framed CCTV headquarters: “Isn’t it good to have a ruling party that can honour its promise?”

Lauri Myllyvirta, a Greenpeace campaigner, said China’s leaders could rightly claim credit for making Beijing blue again, temporarily at least, even if favourable weather conditions had played a major role in the exceptionally good spell.

Since last year, thousands of environmental inspectors have fanned out across the industrial belt around the capital as part of an aggressive clampdown on coal use. Heavily polluting vehicles, factories and construction sites have also been targeted. “There is clear evidence the measures worked,” said Myllyvirta, who said overall PM2.5 levels in Beijing had fallen by 40% from their peak in 2012-2013.

But he sounded a note of caution. Average PM2.5 levels in Beijing remained 65% above the national standard and more than five times World Health Organization guidelines last year. A recent bout of severe smog highlighted the fight ahead.

There are also fears that the crackdown around Beijing is forcing polluting industries to migrate south to regions such as the Yangtze river delta around Shanghai, where smog levels are rising. “The ‘war on pollution’ is far from over … few people harbour illusions,” Myllyvirta said. “But there is also no reason for cynicism as there’s clear evidence the measures worked.”

Wu, 41, abandoned his job as an executive to become an environmentally engaged artist a decade ago, shocked into a career change by images of foreign athletes wearing facemasks at the 2008 Beijing Olympics.

Ten years on, and with the skies over his adoptive home starting to clear, he said he is glad his artwork and photographs, some of which have featured in Greenpeace anti-pollution campaigns, have played a role in increasing public awareness.

“I want to produce work that can push society and the government to make positive changes .... [and] the most effective way to push the government to make changes is through public opinion,” he said. “It shows my work isn’t a waste of time ... It shows the power of art.”

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Wu worries, however, that change may have come too fast. He was among those left shivering when environmental inspectors began destroying coal-fired heaters late last year as part of a push to switch to natural gas or electric heating systems. “It’s only four degrees in here … I can hardly work,” he complained, touring his studio in a thick brown coat.

“I agree with the government that we need lucid waters and lush mountains but … the measures should be more gentle and more human. I can cope with the low temperature, but what about the elderly? What about children?”

In one nearby area, primary school students reportedly suffered frostbite and were forced to study outdoors in the sunshine after their radiators stopped working.

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Wu is also concerned about the environmental damage still being inflicted on less visible regions, where pollution crises have not received the same level of media attention as Beijing’s toxic skies. For one installation, he asked 12 volunteer “disciples” to recreate one of Leonardo da Vinci’s frescos, The Last Supper, in a derelict factory. “The message is that because of pollution, mankind’s last supper could come at any time because of pollution.”

Overall, however, Wu believes China is on the right track. “We should admit the government is trying to do the right thing and we need to recognise that it takes time … to deal with environmental issues,” he said.

If China’s war on smog robbed him of his principal inspiration, he is unperturbed. “There’s no lack of problems to inspire artists in China,” he joked. “Some western artists are jealous of that.”